The present invention relates to a socket assembly for an ultrasound-controlled screwing device.
Such a socket assembly is disclosed for example in the German patent document D-A 42 31 429. It has a coupling means for a rotary connection between a screw connection and a screw spindle of a screwing device. The socket assembly serves additionally for producing an electrical connection between the screw connections and the screwing device, so that the screwdriver due to its electrical conductivity provides a ground terminal of the screwing device. The voltage supply to, an ultrasound resonator arranged on the screw connection is performed through a contact pin engaging the socket assembly. A presumption for an error-free contacting of the ultrasound resonator is an interference-free ground contacting, which in the known screwdriver is not always provided in particular during the plugging on the screw connection.
For eliminating the above mentioned problem, it is proposed in the German patent document DE-A 44 31 675, to arrange on the screw spindle a ground conductor parallel to the contact pin, which similarly to the contact pin engages the socket assembly and contact the screw connection. The additional ground conductor eliminates the contact interferences, however, it makes necessary the provision of its own screw spindle. With the screw spindles having only one contact pin, the problem of electrical ground contacting further is caused.